This application relates generally to the implant of prosthetic joints and pertains, more specifically, to the preparation of the distal femur for the implantation of a femoral knee prosthesis, utilizing a femoral cutting block to assist in establishing the surfaces necessary for locating and securing the prosthesis in place on the femur.
The implant of a prosthetic knee joint requires that the distal femur be prepared to receive the femoral component of the knee prosthesis by cutting the bone of the femur to establish accurately located surfaces. Upon implantation, the femoral component will rest on these surfaces. As used herein, when referring to bones or other parts of the body, the term “proximal” means closer to the heart and the term “distal” means more distant from the heart. The term “inferior” means toward the feet and the term “superior” means towards the head. The term “anterior” means towards the front part of the body or the face and the term “posterior” means towards the back of the body. The term “medial” means toward the midline of the body and the term “lateral” means away from the midline of the body.
Various cutting blocks are available to the surgeon for assisting in guiding a saw blade to make the femoral cuts which establish the desired surfaces. These guides usually have guide surfaces for making four resections and are located and secured on the distal femur, upon an already resected transverse surface on the distal femur. Typically, surfaces are provided for guiding the saw blade during the execution of an axially directed anterior femoral cut, an axially directed posterior femoral cut, an anterior chamfer and a posterior chamfer, all specifically related to the size of the femoral knee prosthesis to be implanted and to the position and orientation of the femoral knee prosthesis on the distal femur. A four-in-one cutting block is a single cutting block for making the four cuts. A four-in-two cutting block comprises two separate blocks for making the four cuts. However, such conventional cutting blocks may exhibit various disadvantages. For example, the two blocks of a conventional four-in-two cutting block are used separately and do not interlock to each other. That is, the first block is used making a first set of cuts comprising the anterior and posterior chamfer cuts and the second block is used for making a second set of cuts comprising the anterior and posterior cuts. The first set of cuts is loosely correlated to the second set of cuts which may decrease the accuracy of the cuts. In addition, these cutting blocks are made of metal which may increase the cost of manufacture. Moreover, because of the high cost of such blocks, they are typically reused for additional surgical procedures. However, this may require sterilization of the blocks which may be costly and inconvenient. In addition, current four-in-one cutting blocks include slots for making chamfer cuts to a femur. However, such cutting blocks are difficult to manufacture requiring expensive equipment and processes to manufacture which makes the blocks expensive to produce. Improvements in cutting blocks and in the manufacture thereof are sought.